Primer assembly and testing apparatus



-- Dec. 22, 194 2.

PRIMER ASSEMBLY ND TESTING Amnmus Filed March 14, "1941 I la INVENTORSClifford WEmuwn.

John Punch RNEYS c. w. BROWN ETAL 1 Patented Dec. 22, 1942 PRIIVIERASSEMBLY AND TESTIN APPARATUS i Clifiord W. Brown and John Pouch,Philadelphia, Pa.

Application March 14, 1941, Serial No. 383,456

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370O. G. 757) 2 Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to us ofany royalty thereon.

This invention relates in general to the assembly of primers for use inammunition and other related arts, and in particular to an apparatushaving features for detecting mis-assemblies.

In previous methods and apparati for assembly of primers, if thepercussion element were put in upside down and not detected oninspection, such primer would result in a dud on firing. Similarly aflash hole in the primer head not drilled entirely through to thepercussion element chamber would result in a misfire.

In carrying out the invention, advantage is taken of the configurationof the ordinary primer cap, in which the bottom portion has an inwarddimple, the under side of the arched primer anvil. This dimple orrecession will clear a circuitclosing pin contained in the assemblyapparatus but if the primer should be introduced in its invertedposition, the pin will yield and close an alarm circuit.

It is, therefore, an object of this invention to produce an apparatusfor the assembly of primers which will detect mis-assemblies.

It is a further object of this invention to produce an apparatus for theassembly of primers which will detect inverted percussion elements andincomplete flash holes.

To these and other ends, the invention consists in the construction,arrangement and combination of elements described hereinafter andpointed out in the claims forming a part of this specification.

A practical embodiment of the invention is illustrated in theaccompanying drawing wherein:

Figure 1 is an elevation in section of a primer assembling apparatus,and

Figures 2 and 3 are elevations in section showing a primer and portionsof the assembling apparatus under conditions of faulty assembly.

Figure 4 is a partial plan view of the base showing the stop assembledthereto.

Referring to the drawing by characters of reference there is shown inFigure 1 an assembly unit comprising in the main, a base I, a nest, orprimer holder 2 and a stop 3 for quickly positioning the nestconcentrically under a punch 4.

In the base I is mounted an electric switch comprising two contactplungers 5 and 6 carried by an insulating plug I screwed into the base.Immediately containing the plungers 5 and 6,

respectively, are the inner metal plugs 8 and 9 which are threaded intoa central opening in t e plug 1 and are held apart by an insulating r nglll. Upper plunger 5 is slidable in a bore in upper metal plug 8 and hasan annular shoulder I2 fitted in a countersunk bore it or plug 8 andurged against the inner extremity thereof by a spring i4 acting againsta threaded spring holder It iitted in plug 8 and having a bore It forthe passage of plunger 5.

hower plug 9 is similarly constructed with an annular shoulder ll in acounterbore l8 and a spring l8 retained by a holder 20 which has a bore2| for the passage of lower plunger 6.

The circuit, which is normally open between plungers 5 and 6, comprisesinsulated lead wires 22 and 23 passing through bores 24 and 25respectively in the base I, a source of current 26 and a signalingdevice 27, shown in the drawing as a bell, but which may consist of alight bulb, relay or some item of control equipment.

Threaded into the head of upper plunger 5 is a screw 28 and force-fittedinto a hole in the head thereof is an insulator 29. Screw 28 serves tofasten the bai'ed terminal 30 of lead wire 22. The insulating plug 29takes the thrust of another plunger 3! contained within the primerholder 2.

Primer holder 2 comprises a cylindrical block with a central bore 32 anda plunger holder 33 threaded into one end thereof. The plunger holder 33is generally similar in structure to plunger holders 8 and 9. Plunger 3|has a shoulder 34 fitted in a counterbore 35 of the holder 33 and aspring 36 for pressure against the shoulder 34 is retained by a,threaded plug 31.

The other end of the bore 32 of holder 2 is adapted to receive a primercasing 38, having a flash hole 39 and a curved anvil 4|] within a primercap 42. Inserted in the top of the primer casmg is a guide 4| for theprimer cap 42 and the punch 4 which is shown in the raised positionafter ramming in the primer cap.

The stop 3 consists of two bars 3a and 3b secured the base by screws anddowels or other convement means, the two bars making a right angle thebisector of which passes through the center of the hole in the base I.It is the function of the stop 3 to conveniently locate the primerholder 2, shown in phantom lines in Fig. 4, in concentric relation tothe hole in the base I and the punch 4.

Ina normal assembly, with the primer cap 42 so disposed that the anvil40 is lowermost in the primer casing 38, no contact is made with plunger3|, which is received in the recess of the anvil. However, if the primercap 42 should happen to be inserted into the primer casing in any otherthan its normal position, for instance upside down as shown in Figur 2,plunger 3| is forced down against spring 36, urging plunger 5 intoelectrical connection with plunger 6 against the action of theirrespective retaining springs and the detector circuit is closed. Onretraction of the punch 43 and removal of the primer, plungers 34, 5 and6 are returned to normal position.

Also, in the case of a primer wherein the flash hole has not beencompletely drilled through, as shown at 44 in Figure 3, plunger 31 willbe actuated to complete the warning or remedial circuit.

The particular embodiment shown is for illustrative purposes only. Manyother types of electric switches for use in the assembling device willreadily suggest themselves to those skilled in the art, and theinvention is therefore not to be deemed as limitedexcept within thescope of the appended claims.

We claim:

1. An alarm unit for detecting faults in the assembly of primerscomprising a primer casing, a primer cup therein, a flash passage in thecasing and an arched anvil in the cup with the hollow of the archopposed to said flash passage, said unit comprising a holder forreception of the primer casing, a resiliently held plunger in saidholder with one end normally lying within said flash passage butterminating short of said arched anvil when the primer cup is correctlyseated in said casing, and means responsive to depression of saidplunger to produce an alarm signal when the flash hole is incomplete orthe cup is in an abnormal position with the hollow of the anvil arch notaligned to receive the plunger.

2. An assembling and detecting device for primers comprising incombination a base block, a primer holding device thereon andpositioning means for said primer holding device on said block, anelectric signalling device in said block comprising a circuit and tworesiliently held conducting plungers in said circuit spaced to hold thecircuit open in normal position and with one of said plungers accessiblefrom above said block but terminating at or below the face of the block,insulating means atop said accessible plunger and. a resiliently heldplunger in said primer holding device aligned with said insulating meanssaid last-mentioned plunger being receivable in the primer andadapted'to be depressed by the inner parts thereof when the latter areassembled in other than the normal position.

CLIFFORD W. BROWN. JOHN POUCH.

